Door operating apparatus



March 13, 1934. E. s. PARVIN DOOR OPERATING APPARATUS Original Filed June 29, 1932 3 Sheets-Sheet l OOoOooOoOOOOoO/@do mv R -Mmvu OCOOON ATTORNEYS.

March 13, 1934. E. GY PARV|N 1,950,627

DOOR OPERAT ING APPARATUS Original Filed June 29, 1952 3 Sheets-Sheet 2 INVENTOR 'dward G, Fbr wf? BY 9G15 #Q ATTohNEYs March 13, 1934. E. G. -PARvlN 1,950,627

DOOR OPERATING APPARATUS Original Filed June 29, 1932 3 Sheets-Sheet 5 Phase ATTORN EYS.

' Patented Mar. 13, 1934 UNITED STATES PATENT OFFICE Edward G. Parvin, Roselle, N. J., assignor National Pneumatic Company, New York, N. Y.,

a corporation of West Original. application June 619,844. Divided and 7 Claims.

This invention involves improvements in door operating apparatus whereby operator is employed in the form oi a linear induction motor.

One of the objects of this invention is to provide in combination with a movable door, a linear induction motor comprising a iixed member and a movable member attached to the door, the sole connection between the xed and movable members during operation of the door being the magnetic eld therebetween.

A further object of this invention is to provide a door operating system of this type including mechanism for converting direct current into alternating current for operating the linear induction motor.

Another object of this invention involves the use of a plurality of mercury switches arranged and interconnected to effect the conversion of direct current into alternating current.

A further object of this invention involves a complete door operating system comprising a door, a linear induction motor, apparatus for converting direct current into alternating current, control device and circuits by means of whichthe door maybe opened and closed.

Another object of this invention is to provide a simplified, efficient form of linear induction motor comprisingk a rectilinear armature and a field mechanism mounted so as to effect movement of the armature when it is energized.

These and many other objects, as will4 appear from the following disclosure, are secured by means of this invention.

This application is a division of my copending application Serial No. 619,844, filed June 29, 1932.

This invention resides substantially in the combination, construction, arrangement and relative location of parts, all as will be described in detail below.

Referring to the drawings- Figure 1 is an elevational view ofthe linearV induction member;

Fig. 2 is a top plan View of this motor showing its armature attached to the door;

Fig. 3 is a wiring diagram forthe field coils or the motor;

Fig. 4 is a top plan View of a converter of direct currents into alternating currents;

Fig. 5 is a side elevational View of this apparatus, l

Fig. 6 is a side elevational view of one of the mercury switches employed in the converter;

Fig. 7 is a diagrammatic end elevational view an electric doorv Virginia 29, 1932, Serialv No. this application October Serial No. 640,222

showing the relative position of four of the mercury switches of the converter; Y

Fig. 8 is a diagrammatic view showing the connections of the mercury switches for converting direct current into two ing current;

Fig. 9 is a diagrammatic view of the complete system as applied to a door; A,

Fig. 10 is a diagrammatic View of a modified form of mercury switch converter; and' Fig. ll is an end elevationaly View of one of the mercury switches of the modiiied apparatus.

The object of this invention is to adapt a linear induction motor to the operation of doors on transportation vehicles, particularly electric vehicles such as subway ears, street cars, electric trains and the like. In operation in such a system, it is usual to employ direct current for the propelling motors for theV vehicles obtained from the third rail or trolley. On such vehicles in order to be able to operate the doors with linear induction motors, it is necessary to have a source of alternating current.

A further object of this invention is to provide therefore a simple apparatus for converting the available direct current into alternating current of suitable form of frequency to operate such linear induction motors.

The complete invention will be best understood by detail reference to the drawings. A g5 suitable linear induction motor is shownin Fig.

l to 3. It comprises a supporting plate 1 to be attached to any suitable or convenient support adjacent the door. Mounted on this plate are the spaced studs 2 on which is slidably 90 mounted a base plate 3 having integral studs A4 in which rollers 5 are mounted, preferably on roller bearings. Secured to the base plate is a laminated core '7 having a plurality of distributing slots 6 in which are disposed the field wind- 95 ings 8. These eld windings are distributed in the slots and interconnected to provide the two phase winding in accordance with well known practice in this art. v

The laminated core 7 with its coils 8 provide 10o the equivalent of the stator of the usual induction motor. At 9 is a magnetic bar of magnetic material such as cold rolled steel or iron which may or may not be laminated in accordance with well known practice. Suitably secured along each side of the bar 9 are the copper strips 10 which are interconnected by transversely extended copper bars 11 mounted in suitable recesses or slots. This armature structure provides the equivalent ofthe squirrel cage phase alternat- 60 rotor of the ordinary inductionr motor. The

' armature bar is attached to the door 12 to be 'i stator are indicated -diagramrnatically vat Fig.

` engagingv the rings.

f against movement on studs 34.

3 and the coils 8 are of course connected and I' distributed in accordance with well known practice in this art.

In Figs. 4 and 5 is shown theV unit for `con-` verting direct current into alternating current of suitable characteristics and frequency for operating the linear induction motor. This. apparatus comprises a suitable supporting plate 15 on which is mounted a small direct current motor 16. Secured to the shaft of this motor is a shaft 17, which is connected to a tubular structure 34 having a shaft-extension at the other end which is journaled in the standard 36V so that. the shaft 17 and tube 34 are rotated as aunit. Secured to theshaft 17 is a drum 18 of Vinsulating material on whichgare mounted six slip rings 19, 20, 21, 22, 23 and 24. Mounted on the standards 32 and 33 is Van insulating slab 31 to rwhich arelsecured sixspring fingers 25,

There is one of these fingers for each slip ring,v each nger having a contact brush 14 for y These spring fingers are resiliently held in contact with the slip rings by means of springs pressing thereon andheld The tube 34 is as shown at 35 in the wall thereof. means of suitable blocks by means of set screws cut away yat a number of points to' provide openings Mounted in the tube by 38` which are secured 39, are a plurality of mercury switches 37a., 8717,

37C, 37d, 37e, 371, 37g, and 3771..v These mercury switches are of a construction Well known in the art and indicated in Fig.V 6. Each switch comprises a glass tube having a disc shaped electrode 50 andI 51 ateach end and provided witha connecting lead as" shown. the tube to form a Vtransverse wall is Mounted` in the insulat- -ing disc 52 having an opening 53 near one edge thereof. In the-tube is a pool of-mercury 54" which interconnects the electrodes 50,` and 51 when the tube is in the position shown in Fig. 6. When it revolves out of this position, the mercury remains `at vthe bottom of the Vtubeand the` insulating` wall 52 separates the mercury into two pools breaking the circuitsbetween the i angles to the plane of the first set.

, same plane as the first electrodes. of these mercury switches arranged which-lie in `Thus the `rst pair in pairs the paper Fig. 4) and lying close to but on opposite sides of the axis `of rotation of the tube 34. The second pair of switches 37e and 37d lie inthe same plane, whichV plane is at and 37g lie in the set and the last set 37g and 37h. lie at rightangles to the third set and in the same plane as the second set. The relationship of the switches of either group of four is shownr in Fig. 7 which shows their position 'diagrammaticallywhen Vviewed from either end along the axis of rotation. As will be apparent fromFig. 7 withv the switches inthe position shown, only the electrodes of switch' 37a are 'I'he pair of switches 37e interconnected-in'rthat'group. In a like manner tion shown therein kIn this converter there are eight planes at rightangles to each other.v

comprises. the switches .3701.v and B'Zblying'in the same plane (the plane of right Upon a 96 degree rotation of these switches .of the stator of the trodes of the four mercury switches of the second set. Slip ring 2O is connected by wire 4l to the left hand electrodeof mercury switch 37j. Wire 41 is `connected' by wire 42 to the left hand electrode'of mercuryswitch 37a. Slip ring 19 is connected by wire 43 to the left hand electrode of mercury switch 37e. Wire 43 is connected by wire 44 to the left hand electrode of mercury switch-37d.V Slip ring 21 is connected by wire 49 rtothe right hand electrode of mercury switch 37g. Wire 49 is connected by wire 50 to the right hand electrode of' mercury switch 37d'. Slip ring 22 is connected by wire 47 tothe right hand electrode of mercury switch 37h; Wire 47 is connected by wire 48 to the lright hand electrode of mercury switch37c.

` With this mechanism a two phase alternating current is secured from a D. C. source which has a frequency of approximately three and onehalf cycles per second whenthe motor is operating at approximately 200 revolutions per minute. It will be noted yfrom an'r examination, of Figs. 4, 5 and 8. that current flows through a pair of mercury switches for every 90 degrees of revolution andr flowsY through they alternating pairs of switches ofany set` in opposite directions. v Referring to Fig. 8 it should be noted that in the actual structure, switch 37C will liebetween switches 37a and 37b in front thereofV and switch 37d will be in the same position in back thereof. In other wordsif these four switches were placed in longitudinalcoincidence, they would be ina position shown in Fig. 7 but are longitudinally displaced in pairs so thatthey may be placed as close as possible to ring again tok Fig. 8

theaxis of rotation. Referwithi the switch in the posi- (which corresponds to their position in Fig. 4) current flows from the D. C. source through wire 45, switch 37a, wire 41,

-phaseNo 2, winding'wire 43, mercury switch 37e andiback through wire 46 tothe other side'of the current source. This causes the current to build up in phase No.2 `winding'a'nd then to die olf as thecircuitis broken to givethe first half of theVV alternating current wave. Current does lnot now at thisftime through any of the other mercury switches because the hole 53 in the transverse wall of these switches, is in such a position for all 4the other six switches'asindicated for one set in` Fig'. 7 so that the mercury is', divided into two poolsfinsulated in each other.

(assume clockwise'rotation Fig. 7) current will flow this time' through switch 37o which will ynow be in the previous position of `switch 37a and current will also iiow through switch 37g.

In pmsing from 4one switch to the other the currentY must flow through phase No. y1 winding by the way of wires 47 and 48 so that this winding l.is nowV energized for the next halfA of the wave;y These windings represent the windings motor. The switches are cross-connected so that thesuccessful half waves lil-0 spring finger v'or alternations of the current form a composite output current in the form oi an alternating current comprising positive and negative altera.- tions. As indicated in Figs. 4 and 5, the switches are connected to the slip rings which are in turn connected to the A. C. output wires and the D. C. input wires.

A complete door operating system is shown in Fig. 9. At 66 is a suitable D. C. current source, one terminal of which is grounded and which source may represent for example, the third rail or trolley, if desired. Of course, suitable voltage providers would be employed in order to cut the voltage down from that of the third rail to a suitable voltage for operation of the door apparatus. However, this is all well known to those skilled in the art and hence the source 66 will be taken as direct current source. The other terminal of this source is connected by wire 67 to one terminal of the door operated switch 68 which is closed when the door is in closed position as shown. The other terminal of this switch is connected by wire 69 to spring finger 71 of a suitable control switch 70. This switch has iive other spring fingers 72, 73, 74, 75 and 76. The operating member of the switch is provided with two contacts 77 and 78 as shown. The switch is shown in the position when the door is closed.

Spring fingers 76 and 73 are connected together and grounded as indicated at 79. Spring finger 74 is connected by wire 83 to one terminal of door switch 84 which is normally open when the door is closed. The other terminal of this switch is connected to wire 67. Spring fingers 72 and 73 are connected by the wires 80 and 81 to the armature windings of the motor 16. Connected across these wires is an electromagnet coil 82 which controls a normally open switch 62. Wire which extends from a suitable current source, preferably the same source 66, is connected to one or" Athe D. C. input slip rings and is connected by wire to one of the terminals oi' eld winding or" motor 16. The other wire 61 from this source is connected to the switch 62. The other D. C. slip ring is connected by wire 63 to the Xed contact of the switch 62 and by wire 64 to the other terminal of the iield winding of motor 16. The four slip rings are connected through their corresponding spring fingers to the eld windings 8 vof themotor' by means of wires 85, 86, 87

and 88.

Connected in wire 6l is in an electromagriet 97 which, when energized, withdraws the pivoted latch bolt 98 out of the path of the door Vto unlock the door.

To open, the door switch is operated to a position so that contact 77 interconnects spring fingers 71 and 72, and contact 78 interconnects spring iingers and 76. Current then flows from source 66 through wire 67, switch 68, wire 69, spring finger 71, contact 77, spring finger 72, wire 80, the armature of motor 16, wire 81, 75, contact 78, spring finger 76, and back through the ground connection 79 to the other side of the current source.

At the same time that the armature of the motor is energized, the electromagnet 82 is energized closing switch 62. Current then flows from the source through wire 60, wire 65, field winding of motor 16, wire 64, switch 62, and back to the other side of the current source through wire 6l and electromagnet 97. The enl ergization of magnet 97 withdraws bolt 98 and unlocks the door. Y At the same time directeurrent is supplied to the direct current slip rings. Motor 16 is thus energized and causes the converter to operate, with the result that two phase alternating current is supplied to the winding 8 of the linear induction motor to provide a moving field equivalent to the revolving field o an induction motor. This varying will introduce currents into the short circuited copper bars of the armature 9 causing reaction which is produced so as to cause the door to open. As the door opens switch 84 closes and,' as the door attains full open position, switch 68 opens deenergizing the system. To close the door switch 70 is operated back to the position shown in Fig. 9 to eiect reversalof motor 16 whereby alternating current is supplied to the linear induction motor to cause the door to close. Just as the door is fully closed switch 84 is opened, with the result that the motor is deenergized.

With the above description it will be apparent that with a. single control switch the converter is put in operation and the linear induction motor energized to open and close the door, and the door operated switches effect deenergization of the motor as the door reaches its limit of travel in each direction.

Experience has shown that with a mechanism of this type the door operates satisfactorily and opens and closes within the speed requirements of the present practice of door operation when the motor is supplied with an alternating current of about a frequency of three and one-half cycles per second. The frequency can, ror course, be controlled by the speed of operation of motor 16 which likewise may be readily controlled as desired. Although the actual speed of the door, operated with such a mechanism, appears to be somewhat slower than thatat'- tained by the use of fluid pressure engines, the time required to open and close Ythe door is the `same with a current of such a frequency because the door starts more quickly. Another Yadvantage of this system is that a door of light constructiony can be employed and since its only connection with the moving force is provided with a magnetic field, there is no danger'of injury to passengers struck lby the door. The door .being of sical connections to operate it, it easily stops when it strikes a person in 'its path when closing. There are many other advantages 4of this system, such as the simplicity of the equipment involved eiiecting an elimination or" compressors, reservoirs, pipes, valves Vand engines, as distinguished from the present common practice of employing fluid pressure apparatus for operat ing the doors. The invention has many other advantages to those skilled in, the art.

The mercury switch converter may Vassume forms as illustrated for example in Fig. 10 where only two mercury switches are employed, each having a common electrode and four separate electrodes positioned at 90 degrees with respect to each other as illustrated in Fig. 11. These independent electrodes are shown, and when the switches are revolved on their axis, an alternating current is produced similar to that produced by the arrangement of Fig. 8. 1n the case of this arrangement, the transverse wall with an aperture is not necessary since the mercury pool remains at the lowest point of the tubes and the individual electrodes dip into it as the tubes 90 and 91 revolve. The common electrodes 92 and 93 in the form of light weight and having nov phy-y cross-connected, as

, armature.

discs, are always in the mercury similar to the electrodes 50 and 51 electrodes are'likevvisey in the form of discs. `The direct current to the modified arrangement of Fig. 10 is supplied to the common electrodes 92 `and 93 through the wires 94 and 95.

With reference to the motor itself, if desired, springs may be interposed between the supporting `plate 1 and the base plate 3 so as toV resiliently holdl the rollersV 8 in contact with the Likewise, if desired,` and as shown, these springs may be eliminated and the mag- Vnetic attraction between the core '7 and the illustration, but rather to the scope of the apdirection.

pended claims.l Y, n

What I seek to secure by United States Letters Patent is: l

l. The combination as described comprising a movable door, an armature bar on said door, a xed support, a stator having windings therein movably mounted on said support for movement toward andV away from the door, and rollers journaled on said stator and contacting Vwith said bar to limit the movement of the stator toward the bar and vmaintain a desired air gap when the stator is energized.

2. A door operating system as described comprising `a movable door, a magnetizable bar secured thereto, magnetizable windings mounted adjacentk said bar, means converting direct current into alternating current, connections from said means yto said windings to supply alternating current thereto, and door operated switches for deenergizing said converting means as the door attains itsV limit of movement in either 3..'The combination with a door and a linear induction motor associated therewith for movingit, of means for converting direct current into very Ylow frequency alternating current, a i D. C. input circuit to said means, an A.. C. output of the tube of Fig. 6, which the above description it` will be apparentk "in other physical formsof apparatus by circuity interconnecting said means and said motor, means including circuits anda control device in said input circuit for supplyingdirect current to said means whereby alternating current is delivered therefrom tothe motor to cause the door toy move in either `direction and means for deenergizingthe converting means when the door reaches its limit of movement in either direction.

4. The combination with a door'and a linear induction motor associated therewith for moving it, of means for converting direct current into alternating current, a D. C. input circuit to said means, an A. C. output circuit interconnecting said means and said motor, ing circuits and means controlled by the door for cutting of the direct current supply when thedoor reaches its limit of movement in either direction.

5. The combination with a movable door and a linear induction motor associated therewith for moving the door, of means including mercury switches forconverting direct current into low frequency alternating current, circuits for supplying direct currentthereto, ycircuits for delivering the alternating current therefrom to the and means includdirect current circuit for eirecting opening and f closing movement of the door by control of the circuit and means operated by the door near the end of its stroke in either direction for interrupting the direct current circuit.

6. Thecombination with a movable door and a linear induction motor associated therewith for moving the door, ofmeans including mercury switches for converting direct current into alternating current, circuits for supplying direct current thereto, circuits for delivering the alternating current therefrom to the linear induction motor, .and switches in said circuits and operated by the door for cutting off the current supply as the door reaches its limit of movement in either direction.

EDWARD G. PARVIN. 

